November 1, 2009

We seem pleased with the way our senses work in everyday use, and you don’t often hear people dreaming of being able to see in the dark or hearing tiny sounds from miles away. Of course if they did, their wish could be granted immediately. Night vision goggles are available for a few hundred euros, and hearing aids or parabolic microphones for a few hundred more. Smell is another matter: lots of things around us seem written in magic ink that only dogs can see, and every one of us has wished at some point to be able to sniff a dropped scarf and run in the right direction to tell the owner you love her. But a smell in the air is made of matter, not light waves or sound waves, and you can’t multiply matter.

What you could do, in principle, is turn up the volume button inside our head. We know there must be one, because our smell acuity varies quite a bit from day to day. Imagine getting hold of it and setting it to full. I have experienced this, and it is wonderful. I once designed a lily-of-the-valley molecule called Lioral containing an atom of sulfur. It was smooth, powerful, had a pleasant sucked-silver-spoon angle to it reminiscent of helional and was much liked by perfumers. It took me a long while to realize it did something more than just smell. I remember coming up for supper from my home office where I had just been sniffing a new batch sent by our chemists, taking a sip of a cheap chardonnay and finding it as good as a Montrachet: powerful ,rich, deep and seemingly going on forever in a russet-apple and walnut style.

A few weeks later we had some guests over and one was a former editor of a women’s magazine who declared herself indifferent to perfume. I decided to try an experiment, and gave her some of our Lioral to smell. She absent-mindedly waved the smelling strips under her nose for a few minutes, whereupon I handed her a strip of Mitsouko, a fragrance she had earlier dismissed as just so-so. Her reaction was gratifying: she started crying, looking at me fixedly through her tears and eventually said “Now I understand”.

There may be other ways of doing this. A group of scientists at the University of Auburn, Alabama headed by the Russian-born polymath Vitaly Vodyanoy have recently discovered that metal nanoparticles made of zinc increase measured smell responses in rats by as much as fivefold. Remarkably, it has to be zinc: gold or platinum nanoparticles don’t work. The reason this happens is unclear, but Vodyanoy and his colleagues have found zinc nanoparticles everywhere in the body, so this may be a natural process. If it works on humans (do not try this at home) and if we could control it, we could at last walk the dog and discuss with it what news are floating in the evening air.